Displaying items by tag: Research

US: A team at the University of Princeton has developed a new alternative cement using oyster shells. The team says that the oyster shells provide calcium carbonate in the form of aragonite, along with biopolymers. Together, these raise the resulting cement’s crack resistance by 19% and its ductility by 17% compared with ordinary Portland cement (OPC).

Team leader Reza Moini said “Our bio-inspired approach is not to simply mimic nature’s microstructure, but to learn from the underlying principles and use that to inform the engineering of human-made materials. One of the key mechanisms that makes a nacreous shell tough is the sliding of the tablet at the nanometer level. Here, we focus on the mechanism of tablet sliding by engineering the built-in tabulated structure of cement paste in balance with the properties of the polymer and the interface between them. In other words, we intentionally engineer defects in the brittle materials as a way to make them stronger by design.“

China: A new study from Hong Kong Polytechnic University showcases sustainable cement production methods, focusing on low-clinker cements and alternative solutions for incinerator fly ash (IFA). The research demonstrates that using carbonated-washed IFA mixed with slag, coal fly ash, or metakaolin can replace 60% of Portland cement, forming ternary blended cement. This approach reportedly reduces the carbon footprint of cement production.

The study found that slag was the most effective, improving pore structure and increasing ettringite and hemicarboaluminate formation with a blend of 40% slag and 20% IFA. It achieved 90% of the compressive strength of pure Portland cement after 90 days.

The researchers said "This study demonstrated the promising potential of the blended cements to simultaneously divert IFA from landfills and reduce the clinker content of cement."

Philippines: A recent study from Cebu, Philippines presents a method for reducing greenhouse emissions in the cement industry. The research, supported by the Department of Science & Technology (DOST) of the Philippines, focuses on partially substituting cement with coal fly ash (CFA). According to the University of San Carlos researchers, CFA's efficacy as a cement substitute depends on its source, with variations in quality, performance, and water requirements when used in paste and mortar formulations.

The study evaluated CFA from a Philippine power plant, examining its use as a partial cement substitute. Researchers designed paste and mortar mixtures with different CFA-to-binder ratios and water-to-binder ratios. The study revealed that increasing the amount of CFA in cement up to 20% by weight could enhance compressive strength, ‘outperforming’ pure cement mixtures.

The study concluded that substituting a portion of cement with CFA not only reduces greenhouse gas emissions but also improves the compressive strength of the resultant material.

South Korea: A recent study from Daejeon explored the potential of low-lime calcium silicate cement as a low CO₂ emission alternative to Ordinary Portland Cement. Researchers from the Korea Institute of Geoscience and Mineral Resources examined the setting and flow characteristics of a mixture of Ordinary Portland Cement and low-lime calcium silicate cement under carbonation curing conditions. The study was financially supported by the Ministry of Trade, Industry & Energy's industrial strategic technology development programme.

The study aimed to explore the reaction and microstructural characteristics of these cement pastes. The low-lime calcium silicate cement was synthesised using limestone and silica fume, with varying proportions added to the Portland cement pastes. The research findings suggest improvements in compressive strength with the inclusion of 30% or more low-lime calcium silicate cement, highlighting its ability to enhance the durability and sustainability of construction materials.

US: A research team from Lehigh University has won a three-year, US$2m grant from the Department of Energy's industrial efficiency and decarbonisation office for a project on concrete decarbonisation. The team, including Carlos Romero, director of Lehigh's Energy Research Centre, aims to develop a sustainable concrete binder using calcined clay, reducing emissions associated with Ordinary Portland Cement production. The project collaborates with Buzzi Unicem USA and focuses on processing and testing calcined clay to mimic the properties of conventional cement.

Lehigh's team will explore various low-grade calcined clays, supplied by Buzzi, testing their compressive strength and durability. The goal is to halve the CO₂ emissions of traditional concrete mixes.

Chair of the Department of Civil and Environmental Engineering Shamim Pakzad said "I am excited about the expansion of the research portfolio of CEE departments into this area of greener cement, which opens many opportunities for future research and implementation in industry."

Sweden: Researchers at Chalmers University of Technology, Sweden, have developed a method to simplify the construction of textile-reinforced concrete structures, a move that is expected to lead to more environmentally friendly infrastructure like bridges, tunnels, and buildings. The new technique addresses the high carbon footprint of cement.

This innovation, involving carbon fibre textiles as a replacement for steel reinforcement, enables lighter structures with reduced cement usage, thereby lowering the overall carbon impact. Karin Lundgren, Professor of Concrete Structures at Chalmers Department of Architecture said "A great deal of the concrete we use today has the function to act as a protective layer to prevent the steel reinforcement from corroding. If we can use textile reinforcement instead, we can reduce cement consumption and also use less concrete, thus reducing the climate impact."

The research is detailed in a paper titled 'Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses', which was published in the Construction and Building Materials journal. The study, a collaborative effort between Chalmers University and Gdansk University of Technology in Poland, is supported by the Swedish Research Council.

UK: Heidelberg Materials' Ribblesdale cement works in Lancashire is participating in a pioneering study to assess the use of ammonia as a hydrogen source for fuelling cement kilns. This 12-month feasibility project, conducted in collaboration with engineering consultants Stopford and Cranfield University, has received funding from Innovate UK through its UK Research and Innovation fund.

The research aims to investigate ammonia as a potentially energy-dense, cost-effective hydrogen carrier for cement manufacturing and other industries. Building on Ribblesdale's successful demonstration of using hydrogen in a net-zero fuel mix for a cement kiln, the new project will focus on the most efficient methods for on-site 'cracking' of ammonia to release hydrogen as kiln fuel.

Marian Garfield, Sustainability Director at Heidelberg Materials UK, said “We have already proved the success of using hydrogen as part of a lower carbon fuel mix, but its storage and transportation are currently technically challenging and expensive. Ammonia could offer a more viable hydrogen source that enhances fuel usage and reduces CO₂ emissions. If successful, this project will pave the way for further investigations into the commercial viability of using ammonia as a hydrogen carrier for combustion in cement production and beyond.”

Mexico: Cemex has launched a new process called clinker micronisation, developed at its Research and Development Center in Switzerland. The method enables cement producers to lower the clinker factor of their cement by up to 50%, while maintaining its strength. It also offers the additional benefit of allowing concrete users to reduce the proportion of cement in their mixes.

CEO Fernando González said “We are finding new ways to boost our decarbonisation roadmap in the production of cement and concrete. We remain committed to achieving our ambitious 2030 decarbonisation goals on the path to becoming a Net Zero company by 2050.”

US: Eagle Materials has outlined its climate change mitigation successes in its 2023 Sustainability Report. During 2023, the company increased its production of blended cement products, including Portland Limestone Cement (PLC). It commenced a major CO2 reduction study with the US Department of Energy, and established a Greenhouse Gas Reduction Team to explore new clean technologies. Eagle Materials says that it is currently working to increase the use of alternative fuels at three of its cement plants.

US: The Department of Transportation has announced a US$5m initiative to investigate the use of steel slag in cement and concrete. This will take the form of a collaboration between the Department of Transportation and a selected US-based steel producer and university partner. The initiative seeks to reduce CO₂ emissions in the production of building materials. Prospective participants may view the grant opportunity here.

Transport secretary Pete Buttigieg said "We're proud to make this funding available to help develop the next generation of construction materials so that the future of our transport infrastructure is more resilient, more sustainable and made in America.”

Robert Hampshire, deputy assistant secretary for research and technology and chief science officer, said “This funding initiative will develop and advance innovative materials and technologies that support the nation’s goals to decarbonise the transportation sector by 2050, strengthen resilience of the nation’s transportation infrastructure, and address adverse environmental impacts created by the transportation system.”